...Something for you biologists to take a look at.

L

Leviiathan

Registered Member
These creationalists seem to believe that scientists can
find no genetic evidence for evolution. I am fully aware that
there are people here who are well majored in this domain
of understanding (biology / genetics). The purpose of this
topic is for such people to read what is written in the above
link, and then provide feedback/arguements as to why
it may be wrong (if so). I am more or less just interested in
feedback to the arguements made on that page.


http://www.drdino.com/cse.asp?pg=news&specific=26
 
Evolution...true or false?

Although I am a strong believer in evolution, I have listened tot the arguments of many in the past who do not believe in it. DNA is a crazy thing and I think that it somewhat depends on the complexity of the organism you are looking at. Take for example the single celled bacteria, it is simple and single celled. and has very few if any organelles. I am sure that most of you have heard about these bacteria in the hospitals that are becoming resistant to our antibiotics. WHy does this occur? Evolution is the ability for an organism to adapt to its environment and this little bacteria is adapting and evolving to better suit itself for the environment to save itself, through stronger genes and the ability to fight what we have. It is like when when we develop a new plane that is invisible to radar, someone will find a way to seeit , then we have redesign another way to hide and round and round we go. Humans for the past 20 millions years or so, have had little need to adapt to the environment. We have been healthy, dominant organisms and hence have not really had to evolve. There are signs of our previous selves in our bodies. In our genetic makeup there are thousands of genes that make us, but only a certain precentage of those genes are expressed. In some parts of fetal development, humans have gills where their ears are now. These etrananeous genes could possibly be the leftovers, from our past evolution to what we are today. It is entirely possible with the way that we, as humans, are killing the environment that there may be another evolution of us to better adapt to what we are doing to ourselves. This of course is my opinion, I am not holding that all this is true, so do ot get mad at me for expressing my interests here. :) Thanks for listening and have a great day.
 
terpsrule ...

Have a bit of a problem with:
Humans for the past 20 millions years or so, have had little need to adapt to the environment. We have been healthy, dominant organisms and hence have not really had to evolve
Click to expand...
I do think that considerable adaptation has been required during the mentioned time period though, admittedly, little evolution.

Glad you referred to stages of fetal development. In the earlier stages it is virtually impossible to identify the species the fetus belongs to if I'm not mistaken.

Oh, and welcome to Sciforums.
 
I have to admit I'm a bit of a Neo-Darwinist, I believe that evolution has occured and just because a jigsaw piece "seems" missing doesn't mean it didn't exist at some point.

When geneticists looked at the geneological roots of our ancestry and seemingly can't find our exact route, it might be possible they overlooked something no matter how small it is.

I'm just going to sidestep here to try and explain how I mean.
called
==Source: "Chaos" by James Gleick ===
A man called "Edward Lorenz" discovered something remarkible.
At the time he was working on programming a Cray (computer) to mimic weather conditions, as the reasearch at the time was to develop an accurate method of predicting weather patterns through the use of computer algorythms.

He would input data from weather forecasts and measurements and play them over again and again, and the patterns would follow near enough the same path.

Then one day he decided to start his pattern off from somewhere within it's middle, with the correct number inputted the pattern would continue like all the other simulations, just this time he rounded off the decimal place.

With that one small change, his entire pattern evolved to something completely different from what it was suppose to follow, just due to the decimal places being rounded.

This was the first clue to the renound "Butterfly Effect".
=========================

I mention the above, because that one small calculation threw what was expect out of the window.

I mention this because there is something that seems to be neglected when a mention of evolution is concerned, and that is Bacteria and Virii.

When you get ill your body is attacked by a bacteria or a virii (at least in most cases) and your body has to develop a method of adapting to combat that disease or ailment.

In doing so you might or will defeat the disease but your body now has intergrated into it's design those antibodies, and if that happens to be a womans antibodies they get passed to the offspring.

Now genetics is known to pass the genes of the mother and father along, but what also gets passed along is those antibody patterns, and over time if a creature/race is strong enough a whole disease can be erradicated.

This of course leads onto the problem, that with radiation one of these antibodies could be re-catalysed into a mutant version of it's former disease, in an offspring down the descendant chain, without that disease actually being present in "the wild".

The small antibody changes, weather you had mumps or chickenpox as child acts just like Lorenz's rounded decimal places, and suddenly what would be a direct path you are looking for seems to divert considerably although it is actually present.
 
Chagur,

You are right in that there has been some evolution of humans, and I think the figure of 20 million is a little to big. I guess that what I was saying is that there really have not been any major changes, i.e. hands turning into fins, or anything like that. basically, we are well adapted top life on the earth. as land lubbers and that there really has not been any kind of major climactic change or otherwise to push further into another evolution. Thanks for your response. have a good day.
 
In my opinion....

- the idea of a DNA change rate going on so steady that it can be seen as a clock is quite silly. Contrary to 'clocks of the passed' such as the C14 method, in DNA 'good' mutations tends to be favored. At least that's my interpretation of evolution. My DNA is constantly being repaired as well.

- disproving the DNA clock does not mean you need to believe in Divine Creation.

- the basic ideas of DNA and evolution are not depending on this DNA clock.

- i think the evolution theory is still the most detailed explanation.

- Divine Creation is not falsifiable (you can never prove it is wrong, cause 'the Divinity's ways are mysterious') and as such discussion about it does not end up anywhere.

There has a discussion between a Gladstone and a Huxley around 1885 whether the order of creation mentioned in Genesis could be whispered into the writer's ear by God , as it seems to be similar to the geological record (said Gladstone) . Huxley then goes into detail on whether all plants species are really all evolved/created before all mammals, which he claims by fossil records is not so. Etcetera, see chapter 27 Genesis and Geology in Stephen Jay Gould's book 'Bull for Brontosaur'.

A quote from the article you refer to:
" The evolutionary trees shown in biology textbooks are simply theory, not science. "

That's quite possibly true. The school textbooks are known to copy each other and simplify the if's and but's in every step. Also the simple examples of single genes giving a fenotype rely heavily on a handful of examples, like eye color, hair color and pea plant hairyness. A PhD student i know wanted to use real-life examples of single-gene expressions. She could not find any: most [sorry, can't find the word, i'm not a native english speaker, capacities? ] rely on a number of genes.
This is why I believe many of the dreams biotechnology wants us to dream are false. I read recently that people believed we could help the 3rd world by putting the 'anti drought gene' from a cactus in crops. Utterly ridiculous of course. As most of them empty promises of biotechnology.
Someone else on this forum wants the tomato to make THC (the working stuff in cannabis (marihuana)). I don't think that can be done either, i don't think the tomato has a similar biochemical pathway. Also some biotechnology students in Delft, when i told them about the problems of vitamin A rice, believed they could make a multi-vitamin and all-amino-acid rice. Knowing what i know of genetic engineering I cannot believe that.

But even if the examples in the textbooks are not always presented that well, i think the general idea is quite close to the truth.

I do advise the very readable books by Stephen Jay Gould. Also acceptable to creationists i think.
 
Hi. Iamhamster not a biologist. But hamsters do get exposed to this stuff. So here goes…

Chrisy, you are obviously right about critical DNA. (Excuse me if you already know this stuff.) A mutation in critical DNA leads to death. Very short clock indeed. However higher organism DNA also contains large regions of so called “junk” DNA. Lots of unused stuff lying in there, including some inactive viral code. In the process of building a protein from the DNA template the “junk” DNA is snipped out. Thus a mutation in the “junk” DNA doesn’t affect the organism one way or the other.

You are also right about DNA being constantly repaired. However the repair process isn’t perfect. (I wouldn’t be here typing if it were.) An average mutation rate for “junk” DNA can and has been measured for various species. This “tick” rate was applied to determine how many years passed since related species shared an ancestor. The times didn’t match up with other dating methods. The molecular DNA clock seems to tick erratically. (Don’t think they know why yet. Could be associated with occasional population collapses that reduce DNA variability.) I have read similar controversy concerning the use of maternal mitochondria mtDNA to determine lineage.

Leviiathan, the best answer I have for you is that the world always seems to be a little more complicated than we first imagine. The molecular clock is more complicated than first expected. Theories must be refined as new facts come to light. Science evolves.

Another criticism you may run across is no evidence of speciation. This one isn’t answered by bacteria adapting. (What does it mean to be different species when you reproduce asexually?) The criticism is that there doesn’t seem to be an observed case of one species evolving into another. That is, the offspring could no longer mate and produce viable offspring with member from the earlier species. If memory serves (doubtful these days) several months ago a regulatory gene (Associated with the histo-compatibility complex? Anyone please feel free to jump in and correct me.) has been discovered that may play a role in speciation. A single mutation in this gene could lead to a new species. (Would the gene have to be recessive? Wouldn’t do any good to have a new species with only one member.)

Xev, some of the science taught in school or presented in the lay press is simplified to the point of being fiction. It’s prettied up and sanitized and presented as gospel truth. The evolutionary trees seen in texts don’t show the gaps or left-over pieces that don’t fit. Nor do they show the alterations that must be made as new evidence comes to light. Real science lives and breathes and is messy. Not easy to teach in school.
 
Researchers who used the clock concept for the most part always knew it was an assumption. The rate of mutation if you believe in evolutionary theory shouldn't be constant even for the same gene in two populations exposed to different environments. The different conditions would preference positively the selection of some genes, which actually lower the selective pressures on all others. So even for a gene not being selected, there would tend to differences. Plus as pointed out organisms all have differences in their DNA repair programs and living conditions (which can lead to different types of mutations as well as rates).

This doesn't even really have anything to do with the validity of evolutionary theory.

DNA based trees probably have the distances wrong, but the topology is not necessarily that far off. It isn't an accurate assmption, but it is useful and anything fancy is most likely going to be as bad if not worse and a whole lot more work.

The real reason I would say we aren't evolving in the way it is traditionally thought of is because we have so much control over our environment. However, the frequency of certain genes in our gene pool is going to change anyway due to behavioral differences which are correlated with certain genes. Evolution only requires different frequencies of child bearing nothing more.
 
Something for you biologists to take a look at.

I am a biologist and my expertise is in conservation and evolutionary genetics. There appears to be some confusion here about evolutionary theory, molecular clocks and scientific theory. Instead of posting unsolicited responses to misconceptions that I've read here, I'll just offer explanations in regards to evolutionary theory to whoever has questions. Ask away if you wish.
 
reply to terpsrule

Well, for example,

evolution is a continuous process, it doesn't turn on and off when the environment changes, but natural selection may. Populations evolve, individuals don't.

scientific theories ARE science, therefore phylogenetic trees are science

Molecular clocks are not silly, they are extremely useful for phylogenetic reconstruction. They match up quite well with the fossil record. Of course, it's not an exact clock as we use clocks, but in geological terms, it's a very good clock.

humans, as H.sapiens, have been around about 10,000 years, certainly no more than 50,000 years.

There are many examples of single gene expressions, but many genes are duplicated.

In regards to biotechnology using genes in economically important species is not ridiculous and it's been done and it works.

Just some examples.
 
Ok

I see your stand on molecular clocks and the like, I was not discounting that one at all. I do know that evolution is ongoing process, my point was, that in the past 50,000 years, there has been very little in the respect to human evolution as a population. I also know that there are huge advance being made in the feild of gene therapy and I think it is a fantastic feild.

If I may ask, what is it you do? Are you a researcher in the feild of evolution? Are you a professor?
 
reply to terpsrule

I have a Ph.D. in zoology, my graduate expertise is in Conservation genetics, evolutionary genetics, systematics. I'm not a professor, although I have taught classes in genetics, cell biology, biometry, human anatomy, marine biology at the university level as a graduate assistant.

H.sapiens is evolving continuously, although i agree that phenotypically humans haven't changed much, if at all in the last 10,000 years.

It seems that you are also a biologist. Do you currently have a position in a biological field?

Best, Paul
 
paulsamuel

evolution is a continuous process, it doesn't turn on and off when the environment changes, but natural selection may. Populations evolve, individuals don't.

In your opinion, how is the Earth's now rapidly changing biosphere affecting our evolution?
 
My Job

I do have a BS in biology from the University of Maryland. I actually did a bit of research with plant genetics in college and then moved into toxicology for a bit. Now I am actually in the Sales and Marketing field as an inside sales manager. So I have run the gamut of things in the biological field, soon to move into the booming phara field, hopefully. :) I am looking to go back to grad school and get my MBA in management and healthcare.

To answer your other question, I feel with the onset of global warming and the over population of so much of the world, that natural selection will begin to equalize the ecosystem. With advent of a heating of the natural environment things will start to change and evolution will continue. I dont reall think that there will be a large scale "natural selection" of humans, but something will occur to change things. Of course, you and I will not see it happen. So everything is only speculation.

By the way, you into March Madness? :)
 
reply to Q

There's a couple of different topics in this question.

Our biosphere isn't changing that much. But there is evidence of global warming and humans are affecting the environment. This wil affect evolution of all organisms. There is a recent book out by S.R. Palumbi on this topic.

Although human evolution continues, Human technology and culture protect humans from natural selection. but humans are still affected by disease and environmental toxins.
 
I have to disagree. Natural selection occurs even on organisms that control their environment. The main issue in evolution is the grouping and proportions of various genes. All this requires is differential reproduction rates and seletive breeding. Both of which occur in human populations.

Morphologically people haven't changed much, but penotype isn't the same as morphology. Medecine has drastically affected evolution of many non-morphological phenotypes. Consider vision defects and diabetes especially.

Everyone has misconceptions including me, please don't put forward your experience as a criteria for accepting yours. You should assert your beliefs and ideas so we can pick the ones that make sense, but not simply tear down that which is imperfect as everything we know was built through mistakes.
 
reply to scilosopher

I agree, natural selection occurs in all organisms including humans, but humans are protected from natural selection as well, both culturally and through advances in technology. You rightly cite two examples that support this.

I know phenotype isn't the same as morphology, anyone with a dictionary knows the difference. That is why I said phenotype (morphology is a subset of phenotype).

Your statement "Medecine has drastically affected evolution of many non-morphological phenotypes," is imprecise. But if you're talking about medical corrections of genetic defects, then you are agreeing with me. Humans are protected from selection by technological advances. (BTW, if the vision defects your talking about are near-sightedness or far-sightedness or astigmatism, these are morphological).

Finally, if you have followed the thread, and know evolutionary biology, then you would have read the misconceptions posted here. As I wrote in my original post, I would not offer unsolicited comments, and I have only responded to direct questions (and now, this attack). There are two reasons I did this. 1) Discussions of evolution can run in circles and lead nowhere without an understanding of the fundamentals, which I can offer and 2) I only offered to respond to specific questions because I did not want to, in your words, "assert [my] beliefs and ideas." I will assert nothing of the kind because evolutionary biology is not my beliefs and ideas, it's a natural phenomenon. Also, there's plenty of material out there without me running an evolutionary biology course here.

The last two sentences in your post are uncalled for and reflect either a lack of effort on your part to read the entire thread, or an inability to understand what you've read.
 
Last edited:
Paul,
I would never intentionally attack anyone. If you construed my post as an attack, can you tell me why (so I can avoid making you feel this way in the future)? I simply disagreed. I don't see how the last two lines are uncalled for. I simply meant to ask (politely with please) that you not simply assert truth without reasoning as to why its true. Maybe I was unclear, but I think answers without explanation are often misleading.

I also admit that I didn't give any more substantiation then you, but I assumed that you would interpret my comments in a contemplative rather than dogmatic and defensive fashion. To be clear, even elimination of selection for a certain trait alters the selective pressures on a species and therefore is effectively a selective pressure of its own (ie one could argue that removing a constraint could speed spread of a closely linked, but improved version of a gene. Essentially an effective pressure for the new and improved version).

I never denied there were misconceptions, I asserted it. You are certainly right that to some extent minor changes in eye shape are morphological defects, but I think my point that genetic change is inevitable and even accelerated by medecine would have been apparent. If not one can certainly stick with diabetes and other diseases (which might in some cases be be due to morphological abnormalities in internal organs leading to systemic issues although the situation is not obvious - my main point was that phenotype on a molecular scale is often not apparent to casual observation like the typical examples given in textbooks.)

Not to be argumentative, but to discuss our apparent difference in views, can you give a definition of fitness that isn't circular? Specifically in the feature that the true measure has to explain the change in genetic composition over time?

Please don't attack me in the future, I don't really appreciate it. Whether I can understand what is written or not , it is either mean to say so or not true. In general I don't think you want to be mean or spread misconceptions. If you can clear up any misconceptions of mine please do so, but don't simply question my intelligence. That isn't very productive.
 
You must log in or register to reply here.
Back
Top